First, if you’re using Firefox, and you have several tabs open, please try holding down the ctrl key and tapping tab a few times, just to see what happens. Go ahead, try it right now. Come back to this page and keep reading after you’re done.

If your Firefox is version 3.0 or older, what should have happened is that each time you tapped tab, Firefox switched to the next tab — meaning the tab to the right in the tab bar. Let’s call this the “old tab behavior”.

If you are using the brandest-newest cutting-edgiest version of Firefox, you would see a transparent overlay with up to three thumbnail images in it, of three of your tabs. Each time you tapped tab, it would change the hilighted thumbnail, but it wouldn’t change anything in your main Firefox window until you released ctrl. Another difference is that the tabs in this mode are ordered by freshness, i.e. by how recently you looked at them, which may be different from the left-to-right ordering of the tabs at the top of the Firefox window. Let’s call this the “proposed new tab behavior”. In case you haven’t seen the very latest Firefox yet, here’s what the proposed new tab behavior looks like: